A Gurumootai is normally a person who wears a turban (typically sikhs in India) or in other words has a sack in his head and has a penchant for being a dumbass.
Gurumootai can also mean,One who's level of intelligence is comparable to that of their own ass.
Person 1: Please pick up the garbage
Person 2: nah il do it later
Person 3: your such a gurumootai
Maybe if you weren't such a gurumootai, people wouldn't kick you.
Shut up Monsieur gurumootai !
Ohhh Mary stop being such a Gurumootai